Extracorporeal processing of blood is known to have many uses. Such processing may be used, for example, to provide treatment of a disease. Hemodialysis is the most commonly employed form of extracorporeal processing for this purpose. Additional uses for extracorporeal processing include extracting blood components useful in either treating others or in research. Apheresis of plasma (i.e., plasmapheresis) and thrombocytes, or platelets, are the procedures most commonly employed for this purpose. Also, non-therapeutic devices have been developed to analyze blood which may involve extraction of blood components. For example, some devices can separate blood and plasma, or specific analytes, for purposes of diagnosis.